24 DAVENPORT ACADEMY OF NATURAL SCIENCES. 



ent conlused succession of some of the beds, will justify a passing 

 notice. At the mouth of the creek the thicker beds of the lower lime- 

 stone and shale, in disturbed condition, extend into the river, appear- 

 ing in the ravine as scattered huge blocks for some distance, and then 

 taking the form of an extended level bottom-rock, over which the 

 stream flows. On the east side, in the bank, appears the encrinal 

 limestone, gradually thickening ar.d rising as we ascend, until, from 

 beneath, there cro|)s out a long exi)osure of the shale crowded with 

 broken valves of Orthis and other brachiopods. Opposite, and across 

 the stream, has been opened in the upper limestone and shales a large 

 quarry. Beyond this, over the whole width of the stream — covering 

 several yards — a stratum made up of Spirifer Parryanus rests partially 

 on the encrinal limestone, and another and higher stratum on the coral 

 reef. There is here no doul)t of its position or contents. The Acer- 

 mi laria daviiisoni is prominent and the roughened calices of Cystiphyl- 

 liim ainericanuin lay ahnost parallel side by side. 

 The section here is as follows : 



1. Coral reef, .... 



2. Upper limestones and shales. 



3. Encrinal limestone. 



4. The Orthis beds. 



5. Thick lower limestones and shales. 



TO 



I 2 

 6 



East of the mouth of the stream, on the river bank facing u, is an 

 unusually interesting exposure extending half a mile. 3 and 4 of the 

 above section is well e\|)oscd. 



The Fifth Ravine, through which Cedar Creek flows, lies west of 

 Buffalo, in the edge of the village, the ([uarry of Captain Clarke being 

 its most noticeal)le feature. We call attention to some of its peculiar- 

 ities : In approaching it from the river, the lower limestones are 

 firmer than elsewhere, even the shales sharing in the same characteris- 

 tic. When they carry fossils it is difficult to detach them from the 

 matrix. The upper limestones at the falls are extremely heavy bedded 

 and firm. In this quarry have been found the greater part of the 

 Crinoidea and Blastoidea of the Spirifer Pennatus beds. Prof. Ulrich 

 gathered here most of the bryozoa described and figured in the Eighth 

 Volume of the Illinois Geological Survey. Above the falls, in the 

 edge of the village, appears a rock differing from any other member of 

 the series, cropping out on the banks of the stream for half a mile. It 

 is in regular beds of four to six inches and attaining a thickness of 



