98 Lincolnshire Notes & Queries. 



Blocks Committee), and others were also present. On this 

 occasion everybody was surprised at the large quantity of 

 boulders and rocks of foreign origin that were found on and in 

 the Boulder Clay of the district. In front of the entrance to 

 Thorp Hall, just outside Louth, on the Lincoln Road, was a 

 boulder of Augite-syenite, a characteristic Norwegian rock, 

 measuring 2 feet by I foot 8 inches, by I foot 5 inches, which 

 still retained the scratches inflicted upon it by the ice during 

 the 'Glacial Period.' Up to the time of writing, this is one of 

 the largest boulders of Augite-syenite recorded for Britain, if 

 not the largest. Steps are being taken by Captain Tennyson, 

 the owner of Thorp Hall, to preserve this boulder. 



There is another Norwegian rock which was found in plenty 

 in the Boulder Clays, viz., Rhomb-porphyry. This is so called 

 on account of the large rhomb-shaped crystals of felspar 

 (orthoclase), which are embedded in a fine-grained matrix, 

 which varies in colour from slaty green to purple or brown. 

 These ' rhombs ' are especially striking on a water-worn 

 surface. 



From these numerous finds it would appear that there is a 

 splendid field open for persons having a geological inclination 

 who are fortunate enough to live in the ' second largest county 

 of England.' So far as I am concerned, I shall be glad at any 

 time to render what services I can, and if any of our Lincoln- 

 shire friends would care to have specimens of the commoner of 

 the Norwegian rocks, I shall be only too pleased to have the 

 opportunity of supplying them. Mr. Tuckwell, the Secretary 

 of the Boulder Committee, would, I am sure, answer any 

 inquiries respecting the boulders of his county, or receive any 

 information respecting the erratics of any part of Lincolnshire. 



With regard to the mariner in which the various far-travelled 

 stones have reached their present positions, the following is the 

 view generally accepted by those geologists who make a special 

 study of the subject. 



During the last of the series of great geological events, viz., 

 the 'Glacial Period,' the climate gradually grew colder and 

 colder, and the snow accumulated on the great hill-centres of 

 the Northern Hemisphere, and probably of the whole world. 

 The cause of this it is not necessary at the present moment to 

 discuss.* 



* The subject has been fully dealt with by Mr. P. F. Kendall, F.G.S., in 'The 

 Cause of an Ice Age.' Trans. Leeds Geol. Asm., part viii., 1893. 



