30 DAVENPORT ACADEMY OF NATURAL SCIENCES. 



numbers is unheralded by any apparent change in the rock. They are 

 also unaccompanied by their usually associated fossils. 



The hardened rock of the Spirifer Parryanus beds rests first upon 

 the encrinal limsestone, and when that disappears, on the coral reef. 

 A short distance beyond this, and for the first time in the banks of the 

 stream, are seen thick, heavy strata assuming very gradually something 

 of the usual characteristics of the beds even as to color, the whole still 

 very sparing of fossils. In the bed of the stream for a long distance, 

 in the matter of form, color, and hardness, the limestone seems assim- 

 ilated to the rock on which it rests. The upper member, heavy bed- 

 ded, buff-colored, is seen in place half a mile distant, resting on the 

 hardened layers of the shales, which, though crowded with the smaller 

 fossils, yet refuses to release them from their matrix, owing to the ex- 

 treme hardness of the material in which they were embedded. 



In the Fifth Ravine, where Captain Clarke's quarry is located, is a 

 comparatively limited exposure occurring on the east side of the Falls. 

 Huge blocks have been detached from their place in the bluffs, falling 

 down and standing on edge. Some of these measure several feet across 

 and are two or three feet thick, showing the usual smaller fossils. The 

 lower portion extends in a perpendicular face to the quarry in the lower 

 beds. Above these Falls are a few scattered rocks, but there is no 

 further extension of the rock northward. 



The Sixth Ravine, one mile and a half below Buffalo in the banks 

 of the streem and one mile above its mouth, presents an interesting 

 exposure. The Spirifer Parryanus beds assumes something of its typi- 

 cal form. The upper portion is buff-colored and heavy bedded, 

 almost non-fossiliferous, with a height of five feet. The middle por- 

 tion is composed of the softer clays and shales filled with the ordinary 

 fossils, and is about five feet in thickness. The lower part maintains 

 its ordinary features for two or three feet till it approaches the stream, 

 when, in direct contact with the underlying rock, it gradually becomes 

 firmer and finally assumes the color and hardness of the coral reef. 

 Just as in the Fourth Ravine, a similar change was wrought in the lower 

 portion of the Spirifer Parryanus- beds in contact with the encrinal 

 limestone. One-half mile further north, on the east side of the stream, 

 the shales and shaly limestones are again seen prolific in fossils, while 

 the lower portions rest on the coral reef conforming to its color and 

 hardness. 



SUMMARY AND CONCLUSION. 



The Phragmoceras beds first recognized in the eastern part of the 



