Coal Formation. 61 



In this threefold distribution of the vast series of strata which have 

 hitherto been indiscriminately designated by the common term greywacke, 

 we are, as it were, extending the progressive operations of a general in- 

 closure act over the great common field of geology ; we propose a divi- 

 sion, founded on measurements, surveys, and the study of organic re- 

 mains, analogous to that of the secondary strata, from the chalk down- 

 wards to the coal-formation, established by William Smith, and to the 

 separations of the once-undivided territory of the great tertiary system, 

 effected by Cuvier and Brongniart, Desnoyers, Lyell, and Deshayes. 



To the uninitiated in geology, rectifications in the distribution of strata 

 upon so large a scale may seem calculated to shake confidence in all the 

 conclusions of our science ; but a contrary inference will be drawn by 

 those who know that these corrections have never been applied to con- 

 clusions established on the sure foundation of organic remains, but to 

 those rocks only of which the arrangement had been founded on the un- 

 certain character of mineral composition. 



Coal- Formation. — The Society has received from Professor Ansted a 

 paper on the carboniferous and transition rocks of Bohemia, a country 

 which he visited last summer, directing especial attention to the district 

 between Prague, Luditz, and Pilsen, which he has illustrated by sections 

 made from personal observation. Above the fundamental granite and 

 gneiss he found extensive deposits of greywacke, on which lie, in uncon- 

 formable superposition, disconnected patches of the coal-formation. The 

 age of this coal is well known, from the fossil flora of Count Sternberg, 

 who resided in the midst of it near Swina, to be identical with that of 

 the great coal-formation of England. Mr Ansted gives information also 

 as to the action of trap-rocks in producing disturbances of the strata in 

 this district; and respecting dislocations, by which the greywacke is se- 

 veral times placed on a level with the coal-measures, whilst in some cases 

 the strata are inverted and the coal-measures laid beneath the greywacke. 



We have received an interesting communication from Mr Hawkshaw 

 respecting a remarkable disclosure made in the Bolton railway, six miles 

 north of Manchester, of five fossil trees in a position vertical to the plane 

 of the strata in which they stand. The roots are imbedded in a soft ar- 

 gillaceous shale immediately under a thin bed of coal. Near the base of 

 one tree, and beneath the coal, more than a bushel of hard clay nodules 

 was found, each inclosing a cone of Lepidostrobus variabilis. The bark 

 of the trees was converted to coal, from one-quarter to three-quarters of 

 an inch thick; the substance which lias replaced the interior of the trees 

 is shale ; the circumference of the largest of them is 154 feet at the base, 

 74 at the top, and its height 11 feet. One tree has spreading roots, four 

 feet in circumference, solid and strong. By the care of Mr Huwkshaw 

 these trees have been preserved, and a covering is erected over them. 

 The attendant phenomena seem to shew that they grew upon the strata 

 that lie immediately beneath their roots. 



Mr Barber Beaumont, in a communication respecting these same trees, 



