56 



Dr. T. Wright on Fossil Echinoderms 



line observed in Sicily from the Val di Noto to Polizzi. Nume- 

 rous faults traverse the N.W. half of Malta and the S.E. of Gozo, 

 which have much disturbed the beds, caused the depressions now 

 forming the north and south channels between Cumino and Malta 

 and Cumino and Gozo, and left the islet of Cumino an isolated 

 fragment of the uppermost beds, which attests the former con- 

 tinuity of the land, before these islands were fractured by subter- 

 ranean and denuded by aqueous agency. " The mineral deposits," 

 says Capt. Spratt, " composing this group, have a thickness of 

 800 feet visible above the sea ; they lie nearly horizontal, and are 

 conformable, although there is a great diversity of mineral cha- 

 racter and condition in the series. None of the deposits are 

 wholly destitute of organic remains ; but, on the contrary, they 

 generally contain them in tolerable abundance, and in a good 

 state of preservation/ 5 The strata may be divided into five groups, 

 each of which contains fossils that are special to it, very few of 

 the species being common to the whole series. These, in a 

 descending order, are, 1st, the coralline limestone ; 2nd, the yellow 

 sand-, 3rd, the clay; 4th, the calcareous sandstone; 5th, the 

 hard cherty limestone. 



No. 1. The coralline limestone , consists of a reddish-white 

 calcareous rock, mostly hard and compact, and sometimes 

 changed into an indurated calcareous sandstone. It attains a 

 thickness of 100 feet, but has been much denuded in several 

 localities. Some isolated portions of this bed, from . being 

 slightly variegated in colour, were formerly used for certain 

 durable work, under the name of Gozo marble. 



Fossils of No. 1. 



MOLLUSCA. 



Voluta, cast of a large species. 



Haliotis, ditto of a n. sp. 



Trochus, ditto. 



Spondylus quinquecostatus, Desk. 



Ostrea Boblayei, Desk. 



Ostrea Virleti, Desk. 



Pecten Pandora, Desk. 



squamulosus, Desk. 



Burdigalensis, Desk. 



Area, casts of. 

 Cytherea, ditto. 



BRYOZOA. 

 Eschara monilifera. 

 Escharina, n. sp. 



CRUSTACEA. 



Carapaces and chelae of several 

 species. 



ECHINODERMATA. 



Cidaris Miletensis, Forbes. 

 Echinus Duciei, Wright. 

 Echinolampas Deshayesii, Desor. 

 Clypeaster crassicostatus, var. of C. 



altus. 

 Brissus latus, \Vright. 



imbricatus, Wright. 



oblongus, Forbes, MSS. 



Brissopsis Duciei, Wright. 

 Schizaster eurynotus, Agassiz. 

 Pericosrnus excentricus, Wright. 



Stylastraea. 



CORALLIA. 



