238 Correspondence — E. B. Tawney — M. Jespersen. 



directly and exclusively from the crushing of the superficial rocks 

 as they follow downwards the shrinking nucleus. The former is my 

 view, the latter Mr. Mallet's. Let us clearly understand each other, 

 and there need be no disagreement between us on other points. 



G. POTJLETT SCROPE, 



PALEOZOIC STARFISHES. 



Sir, — In the January Number of this Magazine a list is given of 

 Palaeozoic Starfishes. It is not, however, complete yet. Allow me 

 to call your attention to a paper by Simonowitsch (Sitzungsb., 

 Wiener. Ak. 1871, Band 64), where the following new species were 

 described : — Aspidosoma petaloides, Sim. ; Asterias acuminatus, Sim. ; 

 Xennster margaritatus ; Xenaster simplex. 



This last genus is a particularly interesting one. All the above are 

 from Devonian beds. The following have also been apparently 

 overlooked : — Aspidosoma Arnoldii, Goldf. ; Ccelaster latescutatus, 

 Sandb. ; Asterias rhenana, Miill. 



These will considerably enlarge your list of Devonian species. 

 E. B. Tawnet. 



" CEEEPS." 



Sir, — Happening to read, in your March Number, Mr. E. Mallet's 

 letter "In reply to Mr. Scrope's Observations, etc.," the "Creeps" 

 of the Coal-fields, as described in Lyell's Elements, and in Nau- 

 mann's Lehrbtich der Geognosie, at once occurred to me. Indeed, 

 I should be very happy to learn, and be much obliged to any one 

 who wonld be so kind as to inform me, whether similar causes 

 might act upon a large scale, producing earthquakes, igneous ejec- 

 tions, and even elevation of mountains. 



Supposing a large excavation to have been made by the eroding 

 and dissolving action of subterranean waters (or by other means), a 

 sink-hole or subsidence of the soil may result; but were an up- 

 lifting and fracturing of the floor with a rubbing a total impossi- 

 bility, would this rubbing be sufficient to produce heat? Agreed, 

 heat would result ; let us multiply the masses twice or thrice, 

 perhaps a greater amount of heat arises ? Finally : Some part of the 

 earth's crust having, from any reason, lost its stability or power to 

 resist the tension, creeps upon a large scale taking place, fissures 

 being produced, rubbings would result, a fragment some miles of 

 width rising slowly, dislocations {structure en eventail), upheaval 

 or subsidence of the soil or crust, and igneous ejections or even 

 volcanic phenomena being caused ; would such a state of things be 

 at all compatible with the present state of science — or of nature ? 



" Mi pare pero die farebbe veramente un vano sforzo d'ingegno 

 chi volesse spiegare in questo modo le oscillazioni della crosta del 

 globo." — Stoppani, Corso di Geologia, iii. § 473, 1873. 



" Unter diesem von der Mitte aus abwarts wirkenden Druck 

 bildete sich in dem Feldspathgebirge die facherformige Schieferung 

 aus." — Studer, Geol. der Schweiz, vol. i. p. 172, 1851. 



" Les tremblements de terre, dont la cause est plus mysterieuse, 

 malgre les travaux si remarquables et si precieux de M. Alexis 



