deposit. The country for some miles around is quite level. No teeth were found and consequently the species and perhaps even the genus is not certain, but it is thought to be a Mastodon americanus. Some years ago at the brickyard on Mulberry street in Muscatine, the tusk of an elephant or a mastodon was found. It was so much decayed that it could not be preserved. Later there was found in a ravine in the western part of Muscatine a well preserved tooth of a mastodon. The tooth is now in the possession of P. B. Speer of Muscatine. It is six and three-fourths inches long and three and seven-eighths inches wide. There are five rows of double points on the upper surface, the longest being an inch and a half high. It has two roots. Near Wapello on the Iowa river, about twenty miles southwest of Muscatine, fragments of bones of some large animal were found, also the tooth of an elephant. H. Lofland of Muscatine had the kindness to bring me an impression of the tooth on paper from which I collect the following facts: Length, nine and five-tenths inches; greatest breadth, three and five-tenths inches; fifteen transverse wave like elevations on its grinding surface. It is certain that this county was the home of elephants and mastodons either during the warm period in the Glacial epoch along with the beaver, or immediately at its close. The scarcity of the remains of these animals, it seems, strengthens the view that they became extinct here about the close of the Glacial epoch. The burying of wood and the mastodon at Wilton are likely to have occurred about the same time and from the same cause. After the hills of drift had become clothed with trees, vines and grasses about the same as now, and innumerable little land mollusks found food, deep shade and hiding places beneath old logs and thick leaves, and the American reindeer, Rangifer caribou, was perhaps monarch of our forests, a formation known in the Mississippi valley as the loess was deposited where Muscatine stands. It hardly covers more than three or four square miles coinciding closely with the limits of the city. I am not aware that it exists anywhere else in the county except on the top of Wyoming Hills. The loess at Muscatine rests on drift, a part of which is somewhat stratified and a part may be a sort of river deposit. Bowlders nearly two feet in diameter, coarse gravel, sand and clay may be seen under the loess. This coarse material rises about sixty feet above high water, where its junction with the loess occurs. The base has been pierced in several places in the city to the depth of forty-five to fifty feet, with little change of material except in two instances to find wood at the bottom. The loess rises nearly to the top of the highest hills. Its greatest thickness must be close to one hundred feet. It resembles ashes in texture and color except a slight shade of yellow. It shows little or no stratification, contains no gravel or bowlders. It stands in vertical, exposed walls almost like good rock. The property is believed to be due to lime and very fine sand which on exposure to the air unite and harden. Scattered through the loess in considerable numbers, apparently without regard to order or arrangement, are stony concretions of very irregular forms, tending strongly, however, to be globular, from a half inch or less in diameter to two or more inches. These concretions, almost without exception, are very much cracked on the inside, the cracks extending from at wide opening near the center to a sharp edge close to the surface. They appear as if when first formed they were solid, then the outer surface hardened and became unyielding, and afterward the mass about the center contracted considerably and became too small to fill the space it formerly occupied. Because of these fractures, rarely visible at the surface, what appears to be as hard and firm as ordinary limestone, is reduced to many fragments by a gentle blow. An ordinary sample of the unconsolidated loess when treated with muriatic acid lost twelve per cent of its weight. The material that would not dissolve appeared, under a lens of a power of over five hundred diameters, to be irregular grains of quartz sand. The concretions treated in the same manner lost sixty per cent in weight and no definite grains could be seen with the same power of lens. There is enough iron in the loess to give to brick made from it a bright red color. Vast numbers of land shells are most perfectly preserved in all parts of the loess unless it be near the bottom. These mollusks must have flourished on the hills adjacent to the Loess lake. * * Not one of the fifty-four species of mollusks now inhabiting the rivers nor of the twenty-one species in the ponds of this county is found in the loess, and only five of the twenty-six species belonging to the land. Between Iowa avenue and Chestnut, north of Fifth street, in grading lot 2, block 99, a bone was taken from the loess about eighteen inches long, somewhat flattened and about two inches wide, covered from an eighth to a quarter of an inch in thickness with the same material as the concretions. This was near the bottom of the loess. Between Linn and Pine, north of Sixth, on lot 4, block 124, about thirteen feet below the surface, in the loess, nearly the entire skeleton of a ruminant was discovered. It was so completely decayed that little could be preserved except fragments of the jaws with the teeth, the whole covered the same as the bone mentioned above. Dr. Joseph Leidy, of Philadelphia, at first thought this was an undescribed species of extinct deer and proposed to call it Cervus muscatinensis but afterward he concluded that it was the American reindeer, Rangifer caribou. Since no stratification is observed in the loess, it could not have been disturbed by currents. It therefore must have accumulated in a lake which was subject to little or no change during loess time. The bed of this lake at the close was almost at the top of the highest hills. The top of the bluff along the river was more than one hundred and fifty feet higher along the bluffs than it is now. Supposing the water in the river to have been on a level with the water in the lake, the vast valley between the bluffs, from four to eight miles wide, must have been filled with material similar to that seen along the bluffs under the loess. The loess deposit must have extended some distance into this valley, for it could not have terminated as we see it in the river bluffs. The great river may have been more of a swamp than a river, three or four miles wide. Since the loess was deposited, the river has carried away the material from bluff to bluff, about one hundred and fifty feet deep. The hard Hamilton limestone, the top of which is seen about high water near Pine creek, and low water a mile east of the city, dips below the river to the south and west. The soft blue shale, with its coal and overlying sandstone resting on this, offered but little resistance to the river when it was twenty or thirty feet higher than now, and consequently the bluffs are generally remote from the river, where the latter is now confined by the limestone. The space between the present limit of the river and bluffs of sandstone is nearly level and no doubt underlaid by the limestone over which the river once washed. Muscatine Island owes its existence to the character of the rock in the Iowa bluff. Whether the basis in which the drift under the loess rests was excavated in the rocks before the Glacial epoch, during that time or since, certain it is, the rocks were removed at least to the limestone which is below low water, the excavation filled fifty to sixty feet deep with loose material, on top of which is the loess, and since then the river has returned from near the tops of the highest hills to its present place. It is doubtful if this could have occurred without a change of level. It seems the land must have subsided till the highest points. were but little above the river. Some stream, probably the Cedar, reaching into northwestern Iowa, carried the same kind of water into this Loess Lake that renders the Missouri and its upper tributaries so famous. Here the mud gradually settled as it does now in the reservoir in St. Louis from the water of the Missouri. Patches of loess are known to exist at Clinton, Iowa City and Des Moines, and from twenty to fifty miles of the western border of Iowa was in the great Loess Lake of Nebraska, Kansas and Missouri. After the loess was deposited, the final topographical features of the county began to appear. The river valleys and the picturesque bluffs are newer than the loess. At no very distant day, the river, or a large branch of it, followed mainly the line of Muscatine slough. The Sand Mound, the northern part of which is in the southeastern corner of the county, is no doubt a part of the debris of the sandstones crushed by the glaciers, washed away by the river, or both. The loose material in the river bottoms of the county is alluvium. It is constantly being changed along the rivers from side to side. Rivers have a sort of pendulum motion and the banks yield where they strike. The geology of the county may be summarized as follows, in regard to ages and groups: Devonian Age, Hamilton Group, seen along the Mississippi from the eastern border nearly to the city of Muscatine, on Pine creek one mile above the mouth, and on the west branch of the same creek, about six miles from the mouth, also on Cedar, near Moscow. Carboniferous Age, Coal Measure Group, seen along the Mississippi from the eastern border to a point about two miles west of the city of Muscatine, on Mad creek about four miles from its mouth, on Pappoose creek about two miles from its mouth, and on Lowe's run, three or four miles west of Muscatine. Quaternary Age, Drift, covering all the county except the loess, mentioned above, and the alluvium along the river bottoms. LAND AND FRESH WATER MOLLUSKS. The mollusks found in Muscatine county are many and the Professor describes each and every one by its Latin name. These are omitted, it being taken for granted that none but a scientist learned in the dead languages would be |