486 Annals of the Carnegie Museum. 



stone very pronounced ripple marks are found. These are usually 

 produced on a shallow bottom. (3) The Sharon conglomerate which 

 has at the base a layer ten feet in thickness made up almost entirely of 

 white quartz pebbles shows a near-shore condition. The Meadville 

 upper limestone is a hard layer composed of pebbles of various sizes 

 and kinds, some containing fossils. These pebbles likewise indicate 

 a near-shore condition. (4) The presence of large numbers of fucoi- 

 dal seaweeds, not only in the Riceville but also in the Meadville shale, 

 is still further evidence of the shallow water conditions. (5) Worm 

 burrows are found in many of the shales. This is especially true of 

 the Riceville shales, and of the shaly layers in the Sharpsville sand- 

 stones. (6) The character of the fauna indicates shallow water con- 

 ditions with a more or less muddy bottom. Lingulcz are found rather 

 abundantly in all the fossil-bearing layers except the Meadville lower 

 shale. Liiigu/odiscince are found in all the fossil-bearing layers except 

 the Sharpsville lower sandstone. Both of these animals inhabit near- 

 shore muddy and sandy bottoms. The presence of broken up Lingulo- 

 disctnce shells and fish remains among the pebbles of the Meadville 

 upper limestone is still further evidence of the near-shore shallow water 

 conditions. The fish remains, which are all dismembered and broken, 

 have been washed in, while the shells of the Lingulodoscince have been 

 ground up by the action of the water and the pebbles. (7) The ab- 

 sence of a deep-sea fauna indicates a near-shore shallow water condition. 

 It is true that a few Orthoceratites have been'found, but these were in 

 such a condition as to show that they were broken before being im- 

 bedded in the matrix in which they were found. It would seem that 

 the empty shells had floated in from a distance. Only two specimens 

 of coral were found, one in the Riceville shale, and one in the Mead- 

 ville upper shale. Both of these specimens were poorly preserved. 

 This almost complete absence of the corals would indicate that for the 

 most part the bottom was too muddy for corals to grow. In some of 

 the layers crinoid stems have been found, but in all cases, except occa- 

 sionally in the Riceville shale, these are but small fragments. (8) 

 Several specimens of crinoids have been found in the Meadville middle 

 limestone. This layer is not more than six inches thick, and for the 

 most part is made up of nodules. The presence of so few crinoids and 

 the thinness of the layer in which they are found would indicate a 

 fairly deep-sea condition for a very limited time. 



