1 6 BULLETIN OF THE LABORATORIES 
Perry. The dip from Mt. Perry to Newton appears to be not less 
than 250 feet, with no noticeable change in the relative thickness of 
the exposed strata. The whole distance southeast represented by the 
grouped sections, is about 30 miles. The dip southeast accomplished 
in this distance is roughly estimated at from 300 to 350 feet, or some- 
thing over ten feet to the mile ; but the dip is much more abrupt after 
passing about six to eight miles east of Granville. It would seem from 
observations so far obtained that there is every where a rather abrupt 
decline along a line a short but variable distance from the edge of the 
coal field, so that the sub-carboniferous with a portion of the coal- 
measures extends outward in the form of a flat rim to the more con- 
cave central basin. In some places this line is almost of the nature of 
a fault and causes some obscurity. This line crosses the Licking river 
a mile or so east of Clay Lick. 
In the next paper we shall be able to make more detailed com- 
parisons of the faunae represented. Enough is now known to assure 
us that many species have continued from the beginning to the end of 
this period. In other cases the coal-measures contain forms which 
might be considered the somewhat modified descendants of Waverly 
species. Nevertheless there are many, perhaps a majority of forms 
which do not exhibit a traceable connection with the Waverly or lower 
horizons. How much of this disparity is to be explained by the 
changed conditions of life — how much by the fact that the connection 
was with a different sea basin, and how much these categories leave 
unexplained, bids fair to prove a perplexing question. Such problems 
as these demand careful scrutiny and, if possible, adequate treatment. 
CRUSTACEA. 
Trilobita. 
Only one species of trilobite has been encountered and this is 
fully described in connection with the discussion of Carboniferous tril- 
obites upon a later page of this issue. 
The only other remains suggesting crustacean affinities is the cu- 
rious valve or plate, figure 21, Plate 1 . In some respects this resem- 
bles the valve of an Ostracode crustacean, with a very thick shell. 
