584 AN ALGAL LIMESTONE FROM ANGOLA. 



Localities. — The limestone is from beds near Lobito Bay in the province of 

 Benguella. The localities from which the specimens were obtained are given below — 

 the numbers refer to Professor Gregory's collecting list. 



8 and 10. Catumbella dam. This rock is cream-coloured and very compact. 



2G4. Ilanha Gorge. The matrix in this specimen is coarser, and contains much 

 quartz and some felspar, both oligoclase and microeline. The specimen 

 is weathered, and the nodules stand out clearly, some attaining a length 

 of 1*8 cm. 



271. Beach, one hour S.W. of the mouth of the Hanha River. This specimen 

 is greyer in colour than the rest, and is partially polished. The algae 

 were here associated with Schloenbachia, n. sp. 



290. Coastal Plateau, at the foot of the scarp of the Second Plateau, about G miles 

 from Old Lobito, on the track to Hanha. This specimen is compact 

 and deep yellow in colour. The material from here gave the best con- 

 ceptacles. 



297. This limestone is less compact, and contains a greater number of shell frag- 

 ments forming nuclei. 



The specimens are so similar, especially microsopically, that there seems no 

 reason to suppose they do not all belong to one bed. 



Throughout the observations recorded in this note I have been indebted to 

 Professor Gregory. 



EXPLANATION OF PLATE. 



Fig. 1. Girvanella minima, sp. nov. Section of 264 x 66. 



Fig. 2. Lithothamiiion angol&nse, sp. nov. Longitudinal section of 290 x 33. • 



Fig. 3. „ ,, ,, Transverse section of 290 x 66. 



Fig. 4. ., ., ,, Transverse section of 290x66, showing lines produced 



by compression, due to growth. 

 Fig. 5. ,, „ ,, Group of conceptacles in 290 x 24. 



Fig. 6. ,. „ ,, Conceptacles which have coalesced, forming a band, in 



290 x 66. This shows structure suggesting canals. 



