1894. | NEW YORK ACADEMY OF SCIENCES. 231 
To the S. W. at the point it forms cliffs 70-80 feet high. The 
shale under the laccolite is visible for 150 feet, while a thin shaly 
layer also penetrates the porphyry, as figured by Emmons. 
A ecrumpling of the porphyry ina N. E.and 8. W. direction 
at this point, corresponding to ‘C” in Emmons’ diagram, ap- 
parently indicates the source of intrusion. The rock is an 
exceedingly tough porphyry, and its petrography has been 
treated by Messrs. Kemp and Marsters in their monograph 
(p. 43). One quarter of a mile further south a similar ejection 
appears for fifty feet along shore, rising in a forty foot cliff, this 
being a brick bed rhyolite. Another occurs on the south side 
of Split Rock Point (according to Messrs. Eakle and Marsters), 
a fourth, badly weathered, in the swampy meadow at the head of 
Whallon’s Bay, as noted by Emmons, and the fifth, associated 
with the Utica shale, on the roadway running west, at the south 
of Essex, 94 of the map. 
In addition to Prof. Kemp’s guidance at various points in the 
course of this work, I am indebted to Mr. Gilbert van Ingen, 
Curator of the Geological Museum of Columbia College for the 
identification of the fossils, and to Mr. E. J. Riederer for assist- 
ance in the field at Essex,and for the use of numerous neg- 
atives, many of my own, taken expressly for the purpose, hav- 
ing unfortunately been ruined in development. 
The accompanying map is compiled from the United States 
Coast and Geodetic Survey Charts of the lake front, and from 
the County Atlas for the interior. The latter is quite unsatis- 
factory in regard to its accuracy, but the only one thus far pub- 
lished. 
The United States Geological Survey has not yet issued the 
sheets of the topography of the district ; and there is obtaina- 
ble only the preliminary triangulation of the region, which was 
published in the Adirondack Report in 1879.* 
Except the approximate altitude of Boquet Mountain, no 
data have appeared for the heights of the mountains and hills of 
the vicinity. 
Appendix I: Record of Dikes, see insert. 
APPENDIX II. 
The material collected by Mr. White contains fossils from the 
following geological stages, which are represented on the map 
at the localities corresponding to numbers appended. 
GILBERT VAN INGEN. 
* Progress sketch—Preliminary Triangulation by Verplanck Colvin; 7th An. 
Report Topog. Surv. Adirondack Region, Map 5. 
