Devon and Cormsoalli Belgium, the Eifel, ^c. 295 



in transition and carboniferous strata. If we compare to- 

 gether the labours of M. Von Buch, Count Miinster, M. 

 Beyrich, and Professor Phillips, on this subdivision of the 

 tribe of the Ammonites, the general result is that in the older 

 transition rocks the Goniatites met with possess a simple dorsal 

 lobe, whilst those which occur in the carboniferous series have 

 a divided dorsal lobe. If this observation were rigidly exact, 

 it might be adopted as a distinctive character between strata 

 of the transition and carboniferous epochs respectively ; and 

 it might also be inferred that limestones which contain Gonia- 

 tites, some of which possessed a simple and others a divided 

 dorsal lobe, might be considered as occupying an intermediate 

 station, that is, as belonging to the later portion of the transi- 

 tion series. But in neither case does the rule appear to hold 

 without exceptions, Thus, of the 26 species of Goniatites 

 noticed by Count Miinster in the Fichtelgebirge, the 22 (four 

 being doubtful) which are strictly defined and figured, have 

 all a simple dorsal lobe; but two other species are figured by 

 M. Von Buch, as derived from thence, with a divided dorsal 

 lobe, namely, Ammo7iites incsquistriatus, tab. ii. fig. 10, and 

 A. semistriatiis, tab, ii. fig. 12*. Of 8 other species described 

 and figured by Von Buch, and referred to but not figured 

 by M. Beyrich, 5 are found in transition tracts, and four of 

 these have a simple dorsal lobe, and one a divided dorsal lobe; 

 while of the three species found in the carboniferous series, two 

 have a simple and one a divided dorsal lobe. M. Beyrich has 

 described 18 species of Goniatites, and 14 of these are figured, 

 but in 12 only are the dorsal and lateral lobes given, and of 

 10 of these which are derived from transition tracts, five have 

 a simple and five a divided dorsal lobe; while in the two found 

 in the carboniferous series the dorsal lobe is divided. M. 

 Beyrich enumerates (including the eight new species desig- 

 nated by himself) altogether 42 species of Goniatites, the 

 greater number being derived from the researches of Count 

 Miinster and M. Von Buch, and a few from the descriptions 

 given by Professor Goldfuss and MM. Martin and Sowerby. 

 Of this list four or five species only are referred to the car- 

 boniferous series. Professor Phillips enumerates 3S species 

 of Goniatites as occurring in the carboniferous system of 

 Great Britain and Irelandf, Of these he has represented 

 the dorsal and lateral lobes of 24 species, out of which 21 



* Von Buch, Ueber Goniatiten, in theTransactions of the Royal Academy 

 of Sciences of Berlin, December 15, 1831. 



t Illustrations of the Geology of Yorkshire, part ii. 1836. Mountain 

 Limestone District. 



