146 



HARDWICKE'S SCIENCE-GOSSIP. 



ful, the violet however L being over flower ; a rather 

 boggy descent brought us to the Caldron Snout, 

 another fall of about a hundred feet over ledges of 

 basalt, and it is the continuance of this basaltic rock 

 which forms the celebrated Falcon Clints, irregular 

 craggy cliffs on the Durham side of Tees, which 

 afford a home in their broken and scattered debris 

 for Saxifraga hypnoides, Scdum Fabaria, Galium 

 boreale, Allosorits crispus, and magnificent plants of 

 A. viride ; here, too, occurred not yet exterminated 

 Aspidium Lonchitis, as well as Lastrea abbrcviata 

 and Poly podium ealcareicm. Retracing our way towards 

 High Force, Peucedamun Ostruthium and Rumex 

 pratensis were found near Langdon. Another day 

 spent in exploring was Cronkley Fell on the York- 

 shire side of the river. Scdum villosimi was found in 

 several places in abundant flower, and a long search 

 was made for Polygala uliginosa, but although a plant 

 gathered had the same narrow sepals with slightly 

 anastomosing veins, and equal arils, yet the branched 

 habit and large flowers rendered it very different 

 in appearance from the typical plant. On the summit 

 of Cronkley, like Widdy bank, composed of disinte- 

 grated limestone, occurred Helianthemum vineale, 

 Dryas octopetala, Juncus triglumis, Alsitie vema, and 

 Gentiana vema, and then a descent brought one 

 to the Tees, nearly opposite the Caldron Snout. 

 Keeping by the side of the Maize beck, we crossed 

 the stream by fording it into Westmoreland, and 

 struggled over the boggy slopes of Dufton Fell, 

 in a heavy shower, for some distance, then again 

 forded the stream, and keeping on the north side of 

 Murton Fell, gradually ascended High Cap Nick, 

 one of the most singular views in Britain, like some 

 huge graving dock, the sides of which were more than 

 a mile long ; then ascended Blackstone edge, 2620 

 feet, whence could be seen a fine view extending 

 to the Lake district mountains. While here a thunder 

 cloud was hanging over Murton Fell ; thunder 

 echoing grandly from the rocks around. A walk, 

 about ten miles through pleasant country scenery, 

 brought us to Kirkby Thore, in direct communication 

 by rail with Penrith and the north. 



" ADMISSION OF LAND SHELLS TO THE 

 BRITISH LIST." 



By G. Sherriff Tye. 



IT is satisfactory to note that the question asked by 

 Mr. Loydell, SciENCE-Gossir, September 18S2, 

 p. 214, has awakened the interest of some concho- 

 logists, and elicited various replies from which, let 

 us hope, some knowledge may be gained by students. 

 In my own notes, December 1882, p. 278, respect- 

 ing the admission of certain shells to the British 

 list, I thought my proviso, "in the absence of any 

 information to the contrary," would meet the 

 requirements of the question ; but Mr. R. M. Christy, 



May 1S83, p. 1 12," takes exception to my remarks, 

 because he thinks there is a probability of certain of 

 them having been introduced by human agency. I 

 quite agree with him as to the probability, but we 

 have no reliable "information." 



Touching the sea-port theory (quite a fair one, I 

 freely admit), I may mention that all the localities 

 given for Succinea oblonga in Britain," save one, are 

 near sea-ports, no one has advanced "introduction" 

 in this case, and we need not jump to a hasty con- 

 clusion with regard to Helix villosa. 



When I sent my notes, I omitted to notice Mr. 

 J. T. Marshall's remarks, November 1882, p. 261, 

 which is unfortunate, as he disposes of Clausilia 

 solida, much to my satisfaction. The gentleman who 

 found it, found also a variety of Unio tumidus, 

 which he insisted (to me) was a new species. 



Clausilia parvtila was found at Kinver, by Mr. 

 Grant Allen, then, I believe, a member of the 

 Birmingham Natural Historical and Microscopical 

 Society, now a well-known writer on evolution, &c, 

 and was submitted by him to Dr. Gwyn-Jeffreys, 

 who named it, and who probably has the shells 

 now ; therefore there should be no doubt about the 

 matter, so far as this species is concerned. 



Helix personata. — " It is especially unlikely that a 

 species which has never occurred in England, should 

 be found in Ireland," says Mr. Christy. Does he 

 remember that Limncea involuta and Gcomalaats 

 macidosus are peculiar to Ireland, and as yet have not 

 been found elsewhere ? Really, in nature, many things 

 actually are matters of fact which are, prima facie, 

 "especially unlikely ; " we must therefore be cautious. 



Dr. Gwyn-Jeffreys says, in speaking of this 

 finding of Helix persona/a by Mr. S. A. Stewart, 

 " I have every reason to believe that H. personata 

 is a native of Ireland, and that his specimen was not 

 accidentally introduced." Doubtless the learned 

 doctor has good grounds for his belief. 



To conclude that any of the species about which 

 we are speaking would have been found by collectors, 

 if they occurred in places other than those mentioned, 

 is " begging the question." It would be as fair to say 

 that every locality was known for any given species, 

 yet no collector will assert this. 



Let us look at some recent examples. My corre- 

 spondent, Mr. T. Rogers, added Zonites glaber to 

 our list in 1870, and my friends Messrs. H. & J. 

 Groves added Vertigo Moulinsiana in 1S77 ; these 

 species had escaped collectors until then. 



The theory of migration ! Why have I arrived at a 

 most " illogical conclusion " ? England has mollusca 

 of its own, i.e. the species inhabiting our island are 

 derivative ; it has no species peculiar to it ; they are 

 continental, and came from thence before England 

 was separated from the mainland. 



The migration or spreading of mollusks has been 

 a slow process, some have reached farther than 

 others. Various causes operate to retard or increase 



