1826.] • • Geological Socieltj. 145 



FRS. and HS. PGS. ; Robert Brown, Esq. FRS.; Charles 

 Konig, Esq. FRS.; Rev. Thomas Rackett, MA. FRS. and AS. ; 

 Sir Thomas Stamford Raffles, Knt. LLD. FRS. AS. and HS.; 

 Joseph Sabine5 Esq. FRS. and AS. ; Nicholas Aylward Vigors, 

 Esq. MA. FRS. 



June 6. — A paper was read on a new Genus of Insects, named 

 Oiketicus ; by the Rev. Lansdown Guilding, BA. FLS. 



Also a paper on Methods and Systems in Natural History ; 

 by J. E. Biciieno, Esq. Sec. LS. 



June 20. — The following papers were read : 



Concise Notice of a Species of Ursus from Nipal, a skin of 

 which has been presented to the Linnean Society by H. T. Cole- 

 brooke, Esq. FR. and LS. Sec; by Thomas Horsfield, MD. 

 FLS. The new species of bear partially described in this notice, 

 appears to be nearer in affinity to the brown European species 

 than to the tropical bears, from which the sub-genera Prochilus 

 and Helarctos have been formed. 



Description of a new British Freshwater Helix ; by the Rev. 

 Revett Sheppard, MA. FLS. 



Of the term Oistros, or (Estrony of the ancients, and of the 

 real Insect intended by them in this Expression ; by Bracy 

 Clarke, FLS. &c. 



It is affirmed in this communication, contrary to the opinion 

 maintained by Mr. W. S. Macleay, and noticed in the Annals 

 for May, 1824, that the (Estrus of Linnaeus, and not his 

 Tahanus, is the true CEstron of the Greeks and Asilus of the 

 Romans. 



The Society then adjourned until the 7th of November next. 



GEOLOGICAL SOCIETY. 



June 16. — A paper was read, entitled, " Notes on the Geolo- 

 gical Structure of Cader Idris," by Arthur Aikin, Esq. FGS. 



The author, after describing the outline of this mountain- 

 ridge, details the relative altitude and position of the different 

 heights, the situation of the summit overlooking the crater (in 

 the bottom of which lies " the Goat's Pool ") and the various 

 faces and slopes of the mountain. 



Mynydd pen y Coed, the highest hill which stands out on the 

 southern slope, is found to consist of beds of bluish grey slate, 

 very regular, rising NE by N, at an angle of about 35°, but 

 bending up sharply at tlie NE end so as to increase the angle 

 to about 50°. The successive subjacent beds, which occupy 

 the ground to the edge of the crater, are found to consist of 

 greywakke, compact splintery quartz with crystals of pyrites, 

 and, in parts, ochry and cellular, and quartz-rock, differing 

 from the preceding only by being more vitreous ; which last 

 rest on a blueish grey quartz, rendered porphyritic by a few 



Nev) Series, \oL, x\i, l 



