88 REPORT—1874. 
Notes on Cavern Evploration, by M. Emilion Frossard, in the Vallée de Cam- 
pan, Hautes-Pyrénées, France. By Sir Witt0ovensy Jonzs, Bart. 
On Geological Maps and Sections of West Galway and South-west Mayo. 
By G. H., Kinanan, F.GS, 
On the Occurrence of the Middle Lias at Ballycastle. By G. Lanerry. 
The author stated that Mr. William Gray first directed attention to the occurrence 
of the Middle Lias in the county of Antrim. It is his impression, however, that 
the area in which it is likely to be found is very circumscribed ; indeed some have 
gone so far as to affirm that its presence is only due to boulders having been trans- 
ported thither, by glacial action, from some of the western islands of Scotland. 
But if this be so, why are the boulders not much more widely distributed? The 
author had not seen these blocks under such favourable circumstances as to 
determine accurately whether they bear the marks of ice-action ; certainly none of 
those which he saw were polished, and any striations might have resulted from 
workmen’s tools, as all the blocks had been exhumed either in constructing wells, 
flax-“ dubs,” or other excavations. One thing, however, is certain, that in the neigh- 
bourhood of the ‘“ Workhouse,” Ballycastle, no cuttings to any considerable depth 
have been made without disclosing some of these Lassie blocks. Unfortunately no 
outcrop occurs affording facilities for a thorough examination. Another and very 
powerful reason why it is likely to be found zn situ is that at Ballintoy, a few miles 
off, we have a fine section of the Rhztic and Lower Lias beds. 
Mr. Gray has stated that the following species had been identified and tabu- 
lated :— Hybodus reticulatus, Ag.? ; Ammonites margaritatus, Bl.; Pitonillus turbi- 
natus, Moore; Pecten liasinus, Nyst; Pecten acutiradiatus, Schloth.; Phcatula 
spinosa, Sow.; Cypricardia cucullata, Goldf.; Isocardia cingulata, Goldf. ; Limea 
acuticosta, Goldf.; Avicula novemcoste, Brown ; Rhynchonella acuta, Sow. ; Rhyn- 
chonella variabilis, Schloth.; Waldheimia numismalis ; Pentacrinus, sp. 
Since this list was made out the author has procured Unicardium cardioides, 
Ammonites planorbis, and two other Ammonites not yet identified ; also three casts 
of Pholadomya and two of Astarte; as these latter are merely impressions, it is 
almost impossible to classify them. 
Some of those fossils which have been mentioned are not confined to the Middie 
Lias alone, but are distributed more or less sparingly in the lower beds of the same 
formation ; others, again, are almost exclusively confined to the Middle Lias marls 
in Ireland. 
On a Remarkable Fragment of Silicified Wood from the Rocky Mountains. 
By H. Auteyne Nicuorson, M.D., D.Sc., F.RS.E., and W. H. Ess, M.B., 
B.A. 
The object of this communication was a singular fragment of silicified wood 
which had been obtained from a fossil forest in Colorado. The forest is situated 
near Colorado City, about 7000 feet above the level of the sea, near Pike’s Peak. 
It covers an area of from 1000 to 2000 acres, and exhibits numerous erect silicified 
stumps, which are placed all round a broad depression, at one time apparently 
occupied by an ancient lake. The stumps are usually three or four feet in 
height, and from ten to twenty feet in diameter, and the authors gave reasons for 
believing that they belonged to the same group as the “giant trees” (Sequoia 
gigantea) of California, if not specifically the same. 
The specimen which formed the immediate object of this paper was a fragment 
about six inches in greatest length by three in width. Thin sections, examined 
under the microscope, exhibited woody fibres and medullary rays, but no disks could 
be detected. Chemically, the wood is completely fossilized, and consists essentially 
of silica. A chemical analysis yielded :—water and organic matter, 6:24; silica, 
