TRANSACTIONS OP THE SECTIONS. 113 



and paraffine oil. The Mersey coal-field was one of the very few in Tasmania which 

 are actually worked ; for arthough the extent of coal throughout the island is 

 almost unlimited, there are very few points at which any operations are con- 

 ducted. 



On the Faults of a portion of the Lancashire Coal-field. 

 By A. H. GrREEiT, M.A., of the Geological Survey of Great Britain. 



In this paper a law was enunciated which appeared to govern the directions of 

 the principal lines of fault in the portion of the Lancashire coal-field lying between 

 the meridians of Wigan on the west and Rochdale on the east. 



On the western side of this tract the average direction of the faults is about 20° 

 W. of N. ; as we go eastwards the lines of fracture tend more and more towards an 

 E. and W. direction, till in the neighbom'hood of Rochdale they are found to run 

 from 45^ to 50° W. of N. 



An attempt was made to show, on the principles laid down by Mr. Hopkins in 

 the sixth volume of the Cambridge Philosophical Transactions, that this law was a 

 necessary cousec[uence of the elevating forces which produced the upheaval of the 

 coal-field. 



The iipheaving forces seem to have exerted their greatest force along the north- 

 em and eastern bomidai'ies, increasing in each case towards the north-east corner ; 

 the western boundary seems to have been a line of upheaval of smaller and more 

 unifomi intensity ; and on the south, where the coal-measures pass below the new 

 red sandstone, the force of upheaval has decreased to a miuinnun. • 



Hence it was inferred that the southern and western boimdaries of the coal-field 

 might be considered as remaining imdisturbed daring the upheaval, while its north- 

 eastern corner had been elevated. The extension of the strata produced by this 

 upheaval, as soon as it exceeded their power of cohesion, would cause fissures ; and 

 the dii'ections of these fissures, indicated by theory, coincide very nearly with the 

 observed lines of the principal fiiidts. 



I 



Comparison of Fossil Insects of England and Bavaria. By Dr. Hageit. 

 (Communicated by H. T. Stainton, F.L,S.) 



The author remarked that formerly the fossiliferous strata of Solenhofen and 

 Eichstadt in Bavaria had been considered analogous to the English secondary strata, 

 but that later investigations had established that the latter were considerably older. 

 " I must especially call attention to the fact, that the species described by Gemiar 

 in the ' Acta Academice Leopold,' to which hitherto reference has always been made, 

 are described from specimens the outline of which has been artistically painted and 

 completed. I have often examined the types carefully, and can maintain with cer- 

 tainty that this accoimt of them is correct. The Royal Collection in the Academy 

 of Mimich, and the collection of Dr. Crantz in Bonn, contain together about 1000 

 stones with insects, and, even deducting the double stones, thus represent at least 

 GOO specunens. 



" Having an opportunity a few weeks back of studying very carefully the Munich 

 collection, I was much sm-prised at the splendid preservation of many of the speci- 

 mens. The insects of the Solenhofen strata are almost universally preserved entire ; 

 wings, legs, head, and antennae are in their proper places ; most of the LibeUulcs have 

 thek wings expanded. He who, on the sandy shores of the Baltic, has noticed 

 how depositions of insects are now taking place, will admit that these Solenhofen 

 insects must have been dead when deposited. They woidd be di'iven by the winds 

 into the sea, thrown on the shore dead or dying, and then gradually covered with 

 sand by the rippling waves. This process took place on the Solenhofen strata 

 extremely gradually and slowly, as is evident from another circumstance ; for we 

 frequently find the ca\ities of insects (the head, thorax, and body) filled up with 

 regular crystals of calcareous spar. Hence the pressui-e of the stratum overlying 

 the insect must have been very alight, when such delicate parts as the abdominal 

 segments of a dragon-fly could oppose resistance for a sufiicient length of time to 

 admit of the formation of crystals. 



1861. 8 



