282 GEOLOGICAL NOTES FOR A VISIT TO EOTHLET CRAG. 



means of which the " Little Limestone Coal " was formerly 

 worked in a small way. 



The Little Limestone itself is not well exposed in the 

 Rothley neighbourhood, but plenty of marine fossils can be 

 obtained in the long range of quarries which can be seen 

 extending to the north at Greenleighton when one is looking 

 westward from the crag top. These quarries are in the 

 Great Limestone, and well worth a visit. To the left, still 

 from the same point of view, close to the railway on its 

 southern side, used to be open the famous Elf Hills Quarry — 

 now most unfortunately covered up and lost to sight — in the 

 Four-Fathom Limestone beneath the Great Limestone. It 

 was in the cutting leading from this quarry to the railway that 

 the Great Whin Sill was, in the sixties and seventies, seen 

 invading this limestone and sending slender shoots and 

 strings of the diabase into the baked stone. Fossils were 

 very common in this quarry, and comprised many rarities, 

 such as trilobites in quantities in a baked calcareous shale in 

 the cutting referred to. In the main quarry it was that the 

 well-known foraminifer Saccaminina Carteri was first found 

 by Sir Walter Trevelyan — a form which we fondly hoped was 

 characteristic of this particular horizon in the Bernician. It 

 turned out however afterwards that Saccammina was to be 

 found in the Silurian of Girvan in Ayrshire, in the Jurassic 

 rocks of India, in the glacial deposits round Lake Erie in 

 North America, and actually living in the shallow Arctic Seas 

 round Franz Joseph Land. A few years ago it was found 

 dead, but, undoubtedly recent, on the shore at Sandsend, in 

 Yorkshire, by Miss M. V. Lebour. Thus were our hopes 

 dashed to the ground, and the name "Saccammina Lime- 

 stone," which we had too soon engraved upon our geological 

 maps,' turned to ridicule. 



But although the great Elf Hills Quarry is now but a 

 memory, there is still much of interest to be seen in its neigh- 

 bourhood, especially in connexion with that ever fascinating 

 sheet of intrusive diabase the Whin Sill. This unique sill 

 (for it is the most extensive post- Archaean sill in Britain, and 



