676 Correspondence — Mr. Edward Hull. 



branch of inquiry which he has been pursuing for some years back. 

 Since the publication of Zirkel's work on the microscopical structure 

 of basalt, with figures and descriptions of the crystalline forms 

 of sliced specimens of minerals, students have been placed at a great 

 advantage as regards the augitic group of rocks. We are now much 

 in need of similar hand-books of reference for diorites, diabasic 

 rocks, felstones, and lavas, with their varieties. As Mr. Allport has, 

 I believe, submitted several hundred specimens to examination, I 

 feel sure he has the materials at hand for a valuable work. 



EoYAL College of Science, TrT^wnj-r. TTtttt 



Stephen's Green, Dublin, Nov. 8, 1871. XjDWAKD hull. 



SILICIFIED COBAL ON THE COAST OF SUSSEX, ETC. 



Sib, — The specimens of silicified wood occurring on the beach at 

 Hove, near Brighton, are, no doubt, derived from the Upper Green- 

 sand, and will at once be recognized by those familiar with that 

 occurring on the coast near Axmouth, in South Devon. 



The semi-chalcedonic chert composing the specimens of silicified 

 coral is more characteristic of the Upper Greensand than the Oolite ; 

 that found at Hove exhibits a boring lined with chalcedony, such as 

 may be seen in the Greensand silicified wood. Their greater abundance 

 at Sandown than elsewhere, in which neighbourhood the Greensand 

 is exposed, would be corroborative of such an origin ; though 

 specifically they would be assigned to the Oolite. The specimens 

 I have seen vary in quality, and would appear to be derived from 

 distinct localities. I have seen numberless specimens of the Tisbury 

 coral in collections at Salisbury and elsewhere, so am able to judge 

 of the comparative appearance of the specimens. 



November Uth, 1871. S. G. PekoevAL. 



nynisciBXjXiJ^isriEOTJS. 



Coal Discoveky. — An important discovery of coal has been made 

 at Halesowen, a village on the East Worcestershire side of the Black 

 Country, and within a few miles of Birmingham. Mr. J. S. Dawes 

 has been sinking trial shafts and exploring in this neighbourhood for 

 the last seven years and at length, after an expenditure of £20,000, 

 his enterprise has been rewarded by the discovery of a seam of coal, 

 14 feet thick and of excellent quality. It is believed, from the position 

 and general features of the measure, that its thickness will be found 

 to increase as the work progresses. Enough has, however, already 

 been proved to controvert the theories hitherto held as to the boundary 

 of the coal-field in this direction, and the impending exhaustion of the 

 Black Country fuel supply. The coal lies at a depth of about 420 

 yards, a headway of 1,005 yards having been driven from the bottom 

 of one of the trial shafts. Mr, Dawes intends to continue his lateral 

 excavations 1,000 yards further, through the property of Lord 

 Lyttelton. — The Times, 24th November. 



Errata.— Page -505, last line, /or " H. B. W," read " H-W. B." Page 501, line 

 22 from to'p, for "bends" read "bend." 



