Outlines of geology. 



61 



form crystallizations. The same are found in Europe. As 

 the molluscous families of nautilus and terebratula also oc- 

 cur, we have in them instances of three families which pass 

 through every formation, from those of the present day to 

 the most ancient. 



A few vegetable remains have also been found, either 

 cryptogamous or monocotyledonous. 



148. The transition limestone occupies a narrow belt of 

 very great length in the United States. In North Carolina, 

 Virginia, Maryland, Pennsylvania, and New- Jersey, it lies 

 in a valley, often diversified by hills of moderate elevation» 

 between the first and second ridges of the Apalachian group. 

 It enters the state of New- York in Orange County, and fol- 

 lows for a time the course of the Wallkill. Thence it passes 

 toward the Hudson River, at Newburgh, where it is covered 

 by diluvial gravel, but re-appears at the surface on the east- 

 ern bank at Fishkill. From thence to Rhinebeck it is wholly 

 confined to the eastern side of the Hudson ; here it again 

 crosses the river, and spreads to a considerable width in the 

 neighbourhoods of Kingston and Catskill. At Hudson it oc- 

 cupies both banks of the river, and extends eastward for 

 several miles, but here finally crosses the river. North of 

 Kingston it changes its level, and begins to rise to a moun- 

 stain height, forming the Indian ridge, which, although small 

 when compared with the neighbouring Catskills, equal the 

 Highlands in elevation. This ridge is produced into the Hel- 

 derberg, which passes to the north-west through Albany and 

 Schoharie counties. In the latter it forms a rich valley, and 

 rising again encloses the valley of the Mohawk on both sides, 

 and often with precipitous cliffs. At the Little Falls of the 

 Mohawk it is covered by the formation of red sandstone and 

 grauwacke, but it is speedily seen again, forming the valley 

 of West Canada Creek, and then rises into a table-land, whose 

 southern slope presents the aspect of a mountain ridge. In 



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