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Notice of Geological Surveys. 131 
cylinders, four inches in diameter,—Madrepores in hemispheres 
feet-over, associated with Encrini an inch in diameter, and 
much larger than those in the blue. 'The blue contains Ortho- 
ceratites, and the fragments of large trilobites, one of which, 
called “‘Isotelus maximus,” is figured as reconstructed from the 
proportions of the fragments, and is twenty one inches long. 
These strata are nearly horizontal, having a prevalent dip of north 
fourteen degrees east, and about six feet in a mile. 
Large areas of this rock being uncovered for the purpose of 
quarrying, it is found planished as if by the friction of some 
heavy body moving over it, and marked by parallel grooves, 
which are regarded by Dr. Locke as “diluvial scratches ;” they 
are found at “ Light’s quarry, east of the Miami, and seven miles 
above Dayton, thus rendered ‘particularly interesting by the dis- 
covery in it of ‘diluvial grooves,’ a circumstance which I had 
thought probable from the fact of the planishing or grinding 
‘down of the strata” first observed at Col. Partridge’s quarry, 
“where the upper surface, especially at the apex of its convexity, 
has its roughness nearly: worn off, not by corrosion or by decom- 
position, nor by the attrition of sand and gravel, but by the grind- 
ing of a flat surface, making the work, so far as it went, a perfect 
plane, and leaving the pits of ‘the deepest cavities entirely un- 
touched.”* “ Light’s quarry has been ‘stripped’ of soil,-more or 
“less, over ten acres, and the upper layer of stone is in most places 
completely ground down to a plane, as perfectly as it could have 
been by a stone-cutter by polishing.” - “In many places, grooves 
and scratches in straight and parallel lines, are distinctly visible, 
evidently formed by the progress of some heavy mass, propelled 
by aregular and uniform motion. The grooves are in width 
from lines scarcely visible, to those three fourths of an inch 
Wide, and from one fortieth to one eighth of an inch deep, travers- 
ing the quarry from between north 19°, to north 33° west, to the 
Opposite points in lines exactly straight, and in fascicles of some- 
limes ten in number, eractly parallel; clearly in compact lime- 
Stone, without seam or fault of any kind—and in a surface ground 
down to a perfect plane.” To illustrate these appearances, a por- 
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* These cavities are found, where another layer of the rock lies upon this, to an- 
‘Wer to.salient points in the upper one, and the “ natural surface of the stone is 
Within certain limits as rough as can be conceived, there being sharp teeth, an inch 
long, projecting from one layer and entering the contiguous one.” 
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