Vol. 52.] LLANDOVERY AND ASSOCIATED ROCKS OF CONWAY. 



maximus is found almost at the level of the road, and the black 

 band No. 4 is only jnst visible at the foot of the bank. This band 

 disappears almost at once when traced east or west, and the zone of 

 Rastrites maximus is also lost at the level of the road on either side 

 of the depression. 



The section is, however, very interesting as affording an oppor- 

 tunity of studying the passage from the Llandovery rocks into the 

 Tarannon Shales. There occurs in this place a graptolitic band 

 above the zone of Rastrites maximus. This must be, from its 

 position, either a passage-zone or the lowest bed of the Tarannon 

 Shales. From the character of the fauna presently to be described, 

 we prefer to regard it as a true passage-bed. 



The following is the section seen at this locality, the strata 

 being enumerated in descending order : — 



9. Spotted grey flagstones to summit. Ft. In. 



8. Black graptolitic band (probably passage-zone) 6 



7. Grey flagstones, with hard gritty band about 1 inch 



wide at base 1 8 



6. Shale band ; zone of Rastrites maximus 1 



5. Grey flagstones, unfossiliferous 1 



4. Black shale-band, just visible. 



(The beds are numbered to correspond with those of the stream-section.) 



From the nature of the exposure of No. 4, we scarcely expected 

 to find any fossils. We succeeded, however, in obtaining a few 

 graptolites, but these were too fragmentary for specific deter- 

 mination. 



Zone ofR. maximus, Band No. 6. — This band is easily recognizable 

 by its characteristic fracture and mode of weathering. It has 

 yielded the following graptolites : — 



Rastrites maximus (Carr.). C. 

 Monograptus concinnus (Lapw.). 



spinigerus (Nich.) ? 



Hisingeri, var. nudus, Lapw. 



, var. jaculum (Lapw.). 



C. 



cgphus (Lapw.). 



galaensis (Lapw.). R. 



Monograptus gregarius (Lapw.). 

 E. 



crassus (Lapw.). 



involutus (Lapw.)? 



turriculatus (Barr.). R. 



Petatograptus ovatus (Barr.). 



palmeus (Barr.). 



Diplograptus tamariscus (Nich.). C. 

 Rughesii (Nich.). C. 



It will be observed that in this locality and in the stream-section 

 the zone of Rastrites maximus is characterized by the abundance of 

 Diplograptus belonging to the species Hughes ii (Nich.), tamariscus 

 (Nich.), ovatus (Barr.), and palmeus (Barr.). The first two are by 

 far the most numerous. 



The upper limit of the Llandovery Beds appears to be well defined 

 by the hard gritty band occurring at the base of No. 7. 



8. Fossiliferous Band. — This differs somewhat in lithological 

 characters from the lower graptolitic bands. It is not so black, nor 

 is it so soft, being of a more gritty nature. It yielded the following 

 fossils : — 



