402 Miss E. Hodgson — On the Furness Limestone. 



well as that of rain, they still show remnants of glacial planing 

 and strife, bearing north-east-by-north, and south-west-by-south. 

 These latter may not, however, have been very long exposed to 

 the direct influence of either rain or sea. 



There is a good deal of bare rock to the south and south-west of 

 Birkrigg — inferior ridges out-cropping along the strike. Some of 

 the beds are very rugged and much broken, the blocks having been 

 apparently shifted en masse and carried off; others display almost 

 exact counterparts of those on the shore, but with this notable 

 difference, that there is in the higher rocks a far greater preva- 

 lence of branched channelling and basin-like hollowing of the stone, 

 more rounding off of edges, and more vertical column-like fluting. 



The western edge of the series skirts the lower Silurian hills in 

 long reaches, rather difficult to define, and only, indeed, to be con- 

 jectured even with the aid of borings. It does not appear to thin 

 out greatly, for at Tarn Close Quarry, one mile to the north-west of 

 Ulverstone, within a hundred yards of what must be its junction 

 with the slate, it has a depth of more than sixty feet. Some of the 

 beds here have been found parted by very thin coal-seams, shales, 

 and sandstones, containing SyrmgojJora ramulosa and a small species 

 of lAtliodendron} 



The greater part of this limestone tract is hid under a vast cover- 

 ing of drift, — glacial, fluviatile, and marine. 



It is principally along the western edge or junction with the slate 

 that sinking for iron ore is attempted ; and hence it is principally 

 along the western edge also, beneath a mass of glacial deposits of 

 varying thickness, that the moulded limestones have been disclosed. 

 In fact, wherever a limestone surface has been reached, there invari- 

 ably the upper bed is found to be deeply indented into curious forms. 



The accompanying sketch by my sister is a very faithful repre- 

 sentation of the mouldings as they are shown in the Tarn Close 

 Quarry. (See figure, p. 403). 



This curiously moulded bed is capped by unstratified Boulder- 

 clay from seven to fifteen feet in thickness, containing striated stones 

 of all sizes up to boulders thirteen feet in girth ; none of them are lime- 

 stone. The indentations are all filled with and covered over by a 

 tenacious clay nearly free from stones, which on being carefully re- 

 moved brought away a limy film from the mouldings, leaving the 

 limestone surface rough and pitied. Some of the edgings of the 

 mouldings are extremely sharp. 



The indented blocks represented in the drawing are from three to 

 five feet long between the fissures, two feet broad from the front to 

 the next joint, and eighteen inches in dej^th. The blocks are easily 

 drawn off, when they disclose similar ones behind. The bed uiDon 

 which this moulded limestone immediately rests is divided into four 

 or five thin separate layers, which are extremely regular and 



^ These and the following ill-preserved fossils from the Birkrigg rocks, were 

 ohligingly named by Mr. John Eofe, F.G.S. : — Amplexus coraMoides ; Gam^yophyllum 

 Murchisoni ; Cyathophyllum regium ; Cyathophyllum Stutchburyi ; Lithostrotion 

 junceum ; Zaphrentis, etc. 



