DISPERSAL BY MAN. 233 



invariably among lumps of frozen chalk, and sometimes 

 frozen to the ground ; many dead shells, of all ages, 

 and in every condition of preservation, were also found. 

 The position of the colony, in Mr. Cox's opinion, is 

 suggestive of its having been intentionally introduced by 

 a naturalist's hand, probably some few years ago. Mr. 

 Smith agrees that the species is doubtless an importa- 

 tion, and thinks it probable that specimens recorded 

 as having been found at Beauvais, in the north of 

 France, were also introduced from a more southern 

 locality. Mr. Carrington, writing in the Field, also 

 agrees, remarking that there can be little doubt but 

 that our colony was introduced, ^'either purposely or 

 by accident." A specimen of this shell was in Dr. 

 Turton's collection of British shells marked " Corn- 

 wall ;" the birth-place, Mr. Jeffreys remarks, of many 

 spurious or exotic shells. The Trochus terrestris of 

 Pennant is said to have been discovered in the moun- 

 tains of Cumberland, but it is perhaps doubtful whether 

 that author really intended to indicate the present 

 species, and I have used his name merely because the 

 compilers of the Conchological Society's list have done 

 so. It is curious to find that a colony of H. terrestris 

 was discovered, in 1875, i^^ ^ churchyard in Charleston, 

 South Carolina.^ 



* C. S. B. Cox and E. A. Smith, " Journ. of Conch,," vi. (1891), 

 PP- 377-9; J- T. Carrington, "Field," 29 August, 1891, p. 334; 

 " Jeffreys," i. (1862), pp. 215-16; Pennant, "British Zoology," iv. 

 (1777), p. Ill; and see Gray's "Turton," 1840, p. 9; Mazyck, 

 " Proc. Acad. Nat. Sci. Phila.," 1876, p. 127, quoted by Mr. Smith 

 as above. 



