Prof. T. Rupert Jones — Some Central African Fossils. 557 



degrees of imbedment affect the visible shape; some individuals 

 showing only a triangular outline. The surface is moderately 

 convex, and bears rather strong concentric lines of growth. 



These fossils have a general resemblance to the Iridina described 

 and figured by D. Sharpe in the " Transact. Geol. Soc." ser. 2, 

 vol. vii. pp. 225, 226, pi. xxviii. figs. 2-4. These were from the 

 Karoo Formation at Graaff-Reynet in the Cape Colony. The con- 

 centric markings in the specimens from Maramura are stronger 

 than those in fig. 4 ; and the shell is more oblong, more nearly 

 vertical at the anterior end, rather fuller on the ventral, and 

 straighter on the dorsal margin. It is not so truncate anteriorly 

 as fig. 2, and not so square behind, nor is its umbo so near the 

 middle of the back. The dimensions are — length 20 mm. (hinge- 

 line 15 mm.) ; height 10 mm. We have nothing to add as to its 

 generic relationship ; and, as it differs specifically from Iridina ? 

 rhomboidalis and I. f ovata, it may be distinguished as Iridina f 

 oblowja, sp. nov. 



A portion of the piece of fossiliferous shale, with Iridina (?) oblonqa, sp. nov., from 

 Maramura, north-west of Lake Nyassa, Central Africa. Natural size. 



The Iridina may be regarded as of Mesozoic age, as well as the 

 associated reed-like and grass- like plant-remains, and the pala?oniscid 

 Fishes ; for all these are represented in the same series of strata with 

 the Mesozoic Dicynodon and other Reptiles, Cyrence, plant-remains, 

 and coal of apparently the same period. The wide extension north- 

 ward of the Karoo Formation, as probably i - epresented by these 

 Maramura beds, is an important addition to our knowledge of 

 African geology. 



Prof. Dr. W. C. Williamson, F.R.S., informs me that he has not 

 found in South-African coals " decided evidence of spores, especially 

 rnacrospores, such as we get in so many of the British splint-coals. 

 The nearest approaches have been in the Cyphergat, the bottom and 

 middle Molteno, the Wynberg on the Sand River, and Slater's coal. 



