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(2) Rock of Elliott County, Kentucky:—
This
rock occurs between Isom and Critche's Creeks, near Fielden Post
Office, six miles south-west of Willard, in Elliott County, Kentucky.
Mr. Diller describes it at some length in the ' Bulletin of the
American Geological Survey,'' and, more shortly, in the American Journal of Science.2
It
was discovered by Professor A. E. Crandall, who states that it has a
very limited extent laterally, and so readily disintegrates as not to
form a noticeable feature in the topography. ' It appears to extend in
two diverging lines from Critche's Creek into the "valley of Isorn's
Creek, with several minor offshoots of undetermined, but doubtless
limited, extent, possibly no more than wedge-like projections from the
main dyke between the strata of the coal measures, which make up the
whole height of the hills of this region. The whole length of the dyke
in its greatest surface extension appears to be less than a mile, with
a width of from a few feet to SO feet or more.'3 The rock,
according to Mr. Diller, is compact in structure, dark greenish in
colour, with a specific gravity of 2-781, having embedded in it many
grains of yellowish olivine, uni-
1 No. 38 (with map and illustrations).
2 Vol. xxxii. p. 121. See, also, Science, 1885, p. 65.
3 This
statement is mainly an inference, as pointed out by Mr. Diller, from
the presence of pyrope and ilmenite in the soil. The visible outcrops
of the rock are only five in number— three of them in a line about
three furlongs long; the others being about five furlongs away in
opposite directions from one end of it, which happens to be the spot
where the rock is in best preservation : they are more or less oval in
shape.
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