E. J. Garwood and J. E. Marr — On Carboniferous Zones. 551 



hitherto done, and also to study such marine beds of the Upper 

 Carboniferous (Millstone Grit and Coal-measures) as are developed 

 in this country. 



In 1886, De Koninck and Lohest showed that the Carboniferous 

 Limestone of the north-east of England was divisible into three 

 groups : the lowest, containing a number of corals and certain fish, 

 including Lophoclus Icevissimiis, L. Ag., and Copodus corniitus, L. Ag. ; 

 the middle, with abundance of Chonetes papilionacea, Phill. ; and tlie 

 upper, witli Productus giganteus. Since that time one of us (E. J. G.) 

 has paid considerable attention to the Lower Carboniferous strata 

 of the northern half of the Pennine Chain, and whilst corroborating 

 the views of the Belgian writers as to the relative position of the 

 two Brachiopods above mentioned, has also detected the occurrence of 

 other fossils in a definite order in that district. So far, the following 

 succession has been made out (in descending order) : — 



Beds with Productus cf . JEdelburgensis 1 y - rl 1 9 ■' 



,, P. latissimus J 



,, P. giganteus ^ 



,, Chonetes papilionacea &nA [ Mouiitaia Limestone 



Ghatetes septosus j Series. 



,, Spirifera octopUcata J 



The beds containing Froductas latissimus have now been traced, 

 occupying the same relative position from the Settle district of 

 Yorkshire into Northumberland. 



Starting in the Ingleborough district, a well-marked horizon is 

 found, characterized by very fine specimens of Productus latissimus, 

 occurring at the base of the " Yoredale Series " in thin argillaceous 

 limestone (being the limestone next above the top of the " Lower 

 Scar Limestone " in that district = second limestone of Sedgwick : 

 " Description of a Series of longitudinal and transverse sections 

 thi'ongh a portion of the Carboniferous Chain between Penigent and 

 Kirkby Stephen,"— Trans. Geoh Soc. 1831, vol iv, pi. vi, fig. 1). 



Proceeding northward to Wensleydale, the same fossil is found in 

 a limestone apparently higher in the series, the Hardraw Scar Lime- 

 stone (see Mem. Geol. Survey Explanation of Q.S. 97 N.W., p. 200). 

 In the Cross Fell escarpment P. latissimus occurs in the High Cup 

 Valley in the second limestone above the Lower Scar Limestone 

 (Melmerby Scar Limestone), the latter being characterized at the 

 top by the presence of Productus giganteus. On the other (eastern) 

 side of the Pennine watershed, P. latissimus is found everywhere in 

 the upper parts of the valleys of the Tyne, Wear, and Tees where 

 the "great" or "main" limestone, in which it is here embedded, 

 occurs. The limestone with P. latissimus is, therefore, separated by 

 Several intermediate limestones from the Melmerby Scar Limestone. 



Still further to the north and east, a thin limestone is found to be 

 crowded with P. latissimus on the north-east coast immediately south 

 of Uowick Burn, the bed in which it occurs being separated from 

 the Great Limestone (at a lower horizon) by some thickness of 

 mechanically formed sediments.^ 



1 For further details concerning this section, see Garwood, in " History of 

 Northumberland," by E. Bateson, vol. ii, p. 330. 



