12 THE GENESEE CONODONTS 
raised lines, or grooves, but in one species the lines meander, 
forming a reticulated ornamentation. 
These plates are not liable to be confused with the shells of 
Brachyopods or the scales or plates of ganoid fishes which occur 
in the same rock. They are quite flat and the thinner ones are 
translucent. They have not been noticed from other Conodont 
bearing localities but it is possible that their presence has been 
overlooked. I have figured all the forms that occur in the 
Conodont bed and, if they pertain to Conodonts, these few per- 
haps represent all or nearly all of the species possessing the 
great diversity of teeth illustrated in the following pages. The 
under surface of one of the plates is shown in fig. 3 on Plate 
XIV. Some of them resemble, at least in ornamentation, frag- 
ments of Lingula valves. 
The presence of these sculptured plates in association with 
the Conodonts would seem to throw doubt upon the hypothesis 
of the Annelid origin of these fossils. It is true that certain 
Annelids ( Lepidonotus, Polynoe) are defended by a double series 
of broad dorsal scales, but these are thin chitinous structures 
quite different from the calcareous fossil plates. On the whole, 
the longer I have studied these organisms, the more have | 
become convinced that the true Conodonts have hardly anything 
really diagnostic in common with Annelid jaws. If, as | shall 
hereinafter try to demonstrate, certain of the leaf-like forms are 
of the nature of pavement teeth, then the conclusion seems almost 
unavoidable that the Conodonts must be considered as the denti- 
tion of some primitive type of fishes. It is to be hoped that some 
day the fortunate discovery of the teeth and plates in well- 
preserved natural association will settle the question of the affini- 
ties of these perplexing structures. 
The possible value of Conodonts as index fossils has recently 
been remarked by Dr. Edward Kindle.t “These fossils have 
long been known in the Ohio Shale,” writes Dr. Kindle, “but 
with the exception of a very few species have remained undeter- 
mined and undescribed. When they have been described and the 
species which are confined to the upper and lower horizons of 
the shale distinguished, they will prove to be an invaluable aid in 
correlating the different parts of the Ohio Shales with their 
equivalents in the Chattanooga Shale in Kentucky and farther 
south.” 
In searching for study material the writer was fortunate 
enough to discover a thin layer of decomposed rock adhering 
to the under surface of the Conodont bed. This was subjected 
*Unconformity at the Base of the Chattanooga Shale in Kentucky. 
American Journal of Science, Vol. XXXIII, p. 128. 
