with the apparent solemnity of the great numbers of people, assembled for religious worship, made considerable impression on our feelings. On the 9th May, we arrived at Cincinnati.[021] Since our departure from Pittsburgh, Dr. Baldwin's illness had increased, and he had now become so unwell, that some delay appeared necessary on his account; as we wished also for an opportunity of making some repairs and alterations in the machinery of the boat, it was resolved to remain at Cincinnati some days. Dr. Baldwin was accordingly moved on shore, to the house of Mr. Glen, and Dr. Drake was requested to attend him. Cincinnati is the largest town on the Ohio. It is on the north bank of the river, and the ground on which it stands is elevated, rising gradually from the water's edge.[022] Compact limestone appears here, in the bed of the Ohio, and extends some distance in all directions. This limestone has been used in paving the streets, for which purpose its tabular fragments are placed on edge, as bricks are sometimes used in flagging. The formation of limestone, to which this rock belongs, is one of great extent, occupying a large part of the country from the shores of Lake Erie, to the southern boundary of the state of Tennessee.[023] It appears, however, to be occasionally interrupted, or overlaid by fields of sandstone. It abounds in casts, and {20} impressions of marine animals. An orthocerite, in the museum of the college[024] at Cincinnati, measures near three feet in length. Very large specimens of what has been considered lignite, have also been discovered and parts of them deposited in that collection. We saw here no remains of ammonites. Numerous other species appear to be similar to those found in the limestone of the Catskill and Hellebergh mountains. The soil, which overlays the limestone of Cincinnati, is a deep argillaceous loam, intermixed with much animal and vegetable matter. Vegetation is here luxuriant; and many plants unknown eastward of the Alleghany mountains, were constantly presenting themselves to our notice. Two species of æsculus are common. One of these has a nut as large as that of the Æ. hippocastanum, of the Mediterranean, the common horse-chesnut of the gardens.