bad a 
| 
ee 218 O. C. Marsh on Palcotrochis. 
sidered specifically distinct.* The forms described were found 
in Montgomery county, where they occur in great abundance in 
granular quartz and slaty quartzite, having a vertical range of 
about 1,000 feet, Prof. Emmons attached great importance to 
the fact that they occur in auriferous rock, and he hence inferred 
that the gold must have been deposited as asediment.' Shortly 
after the description of Paleotrochis was published, Prof. James 
Hall, in a letter to Prof. Dana, suggested that these forms were 
merely concretions, an opinion subsequently controverted. by 
Prof. Emmons, who maintained their organic character. 
These supposed corals are usually lenticular in form, often 
resembling two short cones placed base to base. In size, they | 
vary from one-fourth of an inch to two inches in diameter. Eo 
_ The exterior is covered with irregular striz or grooves, which | 
extend from apex to apex. Many of the smaller specimens have | 
at one extremity a rounded knob, and at the other a cavity. 
he following figures, from Prof. Emmons’ Report, represent 
more common varieties, and are here repeated for conven- 
| 
| 
‘ ience of reference, | 
1 | 
{ 
While making some investigations during the past summer 
‘on the structure known as “cone in cone,” the writer’s atten- 
tion was called to these peculiar forms, and their inorganic 
nature was at once suspected. An examination of the interior 
of several specimens clearly indicated that they were not corals, 
and, as soon as microscopical sections could be prepared, they 
were more carefully examined, but no trace of organic struc- 
ture could be detected, the entire mass being evidently a finely 
grained quartz. The specimens examined were undoubtedly 
authentic examples of Paleotrochis, as some of them, preseD- 
ted to the Yale cabinet by Prof. Dana, were sent to him by 
f. Emmons, and the rest were given ‘to the writer by Prof 
W. C. Kerr, the present State Geologist of North Carolina. 
~ It follows, therefore, that this name should in future be drop- 
ped from the genera of fossils. It is not, indeed, impossible, 
or even improbable, that the gold-bearing rocks of North Car- 
- olina may yet be found to be fossiliferous, but up to the present 
time no satisfactory evidence of their being so appears to have 
been brought to light, ‘ 
* Geological Report of the Midland Counties of N. C., p. 62. Also this Journal, 
vol. xxii, p. 389. 
t This Journal, xxiii, p. 278, and xxiv, p- 151., 
