HARRIS OUR LOCAL GEOLOGY. I 7 



In a succeeding volume he speaks of its "being destitute of fossils 

 except in the upper layers, near its junction with the shales." 



These "upper layers," in virtue of their position and character, 

 constitute the upper member of the Phragmoceras beds as they are 

 elsewhere exhibited. The Professor further claims that there were 

 no fossils in these beds, differing from those in the beds above them 

 (the Spirifer Pennatus beds). He overlooked the fact that in the 

 very volume in which the statement is made he had described one 

 of its most characteristic fossils, the Spirifer sithumiifcrus. In the 

 next volume two others equally characteristic, the Phragmoceras ivais hi 

 and Calceocrijius barrisi, were described and figured. Recrossing the 

 river, in Cook's quarries, just below the city, on the bottom-land, and 

 but a short distance from the river and little above its level, was the 

 typical realization of the Phragmoceras beds.* As originally described, 

 the southern portion had been first worked, presenting for years the 

 two marked divisions by which they were distinguished. The lower, 

 answering to Professor Worthen's description, was a fine-grained, grey 

 or dove-colored limestone, attaining a thickness of eight or ten feet, 

 arranged in regular layers of a foot or more in thickness. Irregularly 

 disseminated through the mass was found the greater part of the larger 

 and best- preserved fossils. Conspicuous among them were the Ceph- 

 alopods, Brachiopods, and Crinoidea. Above these were thin, non- 

 continuous layers from two to three inches thick, extending upwards 

 two or three feet, with abundant coralline forms, embracing Cyatho- 

 phyllum, Favosites, Cladopora, Alveolites, and Stromatopora. On the 

 surface of the ground the same forms occurred in abundance, while in 

 a neighboring quarry they were massed together in a reef. As the 

 (quarries were worked northward these layers became gradually thick* 

 ened, till they assumed something of the character of the rock on 

 which they rested, carrying few fossils. Occupying their place was a 

 stratum of one to two feet in thickness, roughened with the broken 

 valves of a shell, in external form closely resembling a Rensselaeria, 

 the greater number partially weathered, and so compacted together 

 that while they existed in large numbers it was difficult to extricate a 

 single individual from the mass without such breakage as to place it 

 beyond all hope of positive identification. This today forms an ex- 

 tended layer capping the limestone beneath, and stretching on a quarter 

 of a mile or more towards the bluff, excluding through the whole 

 distance almost every other form of fossil. 



♦Proceedings of the Davenport Academy of Natural Sciences, Vol. 11., page 261. 

 [Proc. D. A. N. S., Vol. VIL] 3 [ September 17, 1897.] 



