﻿Revieios — Prof. Tschermak — On Volcanic Action. 569 



Two longitudinal sections along the lines mentioned give a good 

 idea of the general connexion of the details. 



As a whole., the structure of the Tyne, Wear, and Tees Coal-field 

 is simple enough, and since Buddie's remarkable papers on the 

 larger seams of the district, the general equivalence of these has 

 been fairly well understood. With the minor seams, however, this 

 is not the case, and every one will appreciate the obligation under 

 •which Mr. Simpson has placed northern geologists and mining men 

 in giving them the results of his observations on the subject. In 

 some instances even now the correlation of the seams is still doubtful, 

 especially in the extreme north. When this is so, a special mark 

 attached to the sections denotes the uncertainty. 



The nomenclature of Coal-seams has ever been eccentric, and here 

 ■we have this brought vividly before us. The names in use m the 

 Tyne district are not those of the Wear Valley, while yet other 

 names are given to the same Coals in the Derwent area. 



The care with which this chart has been drawn up is evidenced 

 by the fact that even the small seams Ij'ing between the Brockwell 

 seam (the arbitrary base of the Coal-measures) and the Millstone- 

 grit are duly entered in their places. In this interval we have the 

 group of beds sometimes referred to as the Ganister series, although 

 the rocks composing it are indistinguishable from those either above 

 or below, and no marine fossils have, so far as we are aware, been 

 found in them yet. The fine-grained white, rootlet-pierced, sand- 

 stones, which give their name to the division, are found both in the 

 beds above the Brockwell seam and in the Carboniferous Limestone 

 or Bernician rocks far below. We are thei-efore pleased to see that 

 Mr. Simpson includes the series (some 300 feet thick) in the Coal- 

 measures proper, in which, indeed, he has, very judiciously, recog- 

 nized no divisions whatever. The entire thickness of the Coal- 

 measures, according to him, from the highest bed known in Boldon 

 Colliery (between Sunderland and Newcastle), and the top of the 

 Millstone-grit, is about 2125 feet. What thickness of upper beds was 

 removed before the deposition of the Permian deposits (the un- 

 CQnformity of which is well shown in these sections), there is of 

 course no means of knowing. 



Mr. Simpson's diagram, while it is indispensable to all local 

 inquirers, cannot fail to be appreciated by geologists and mining 

 engineers everywhere as the latest, readiest, - and most accurate 

 summary of all that is important respecting the Newcasfle Coal- 

 field. G. A. L. 



11. — On Volcanic Action as a Phenomenon of the Universe. By 

 Prof. GusTAV Tschermak, Member of the Imperial Academy 

 of Sciences. Bead 8th March, 1877. (From vol. Ixxv. of the 

 Transactions of the Imperial Academy of Sciences, 1st part, 

 March number, 1877. Vienna.) 



TTIHE author has formerly suggested that all stars in the course bf 



I their development pass through a volcanic phase. The moon's 



mountains have been thought by Hooke, Nasmyth, and Carpenter, 



