116 PROCEEDINGS OF THE NATIONAL MUSEUM vol.78 



Plate 6 



All of the figures are X 4. 



Page 



Figures 1,2. Beyrichona tinea Matthew (see also pi. 7, fig. 4) 43 



1 . A specimen showing the two valves extended. 



2. A left valve. 



Lower Cambrian (Haufordian Clb3): Hanford Brook, 

 New Brunswick (2z). 

 3, 4. Beyrichona tinea planata (Matthew) (see also pi. 7, figs. 1-3.) 45' 



3. A typical or rather large right valve. 



4. A right valve of the usual shape and size. 



Lower Cambrian (Hanfordian C162) : Hanford Brook, 



New Brunswick {2h). 



5, 6. Beyrichona tinea Matthew var. C 43- 



Lower Cambrian (Hanfordian C162) : Hanford Brook, 



New Brunswick (2/i). 

 Beyrichona tinea var. D. 

 Lower Cambrian (Hanfordian C163) : Hanford Brook, 



New Brunswick (2z) . 



7. Beyrichona tinea Matthew vav 43 



A left valve intermediate in characters between the 



type form and the variety planata. 

 Lower Cambrian (Hanfordian C162) : Hanford Brook, 



New Brunswick {2h) . 



8-10. Beyrichona tinea triangula (Matthew) 44 



(See also pi. 7, figs. 8, 9.) 



8. Left valve showing the usual characters of the 

 species. 



9. A smaller right valve. 



10. Left valve differing slightly from the more typical 

 form in outline. 



Lower Cambrian (Hanfordian C163) : Hanford Brook, 

 New Brunswick (2t) . 



11. Beyrichona papilio Matthew (see also pi. 7, figs. 5-7) 43 



A right valve. 



Lower Cambrian (Hanfordian, Clb3): Hanford Brook, 

 New Brunswick (2i) . 

 12, 12.1 Beyrichona rotundata Matthew (see also pi. 7, figs. 11, 12)_. 46 



12. A small but typical right valve. 



12.' The original type, X 2, with surface unwhitened. 

 Lower Cambrian (Hanfordian, C162): Hanford Brook, 

 New Brunswick (2/^) . 

 13-15. Beyrichona triceps (Matthew) 46^ 



13. A right valve with a slightly shorter hinge line 

 than usual. 



14. 15. Two right valves. 



Middle Cambrian (Johannian, C26) : McLean Brook, 

 Dugald Brook, and 1.5 miles west of Marion Bridge, 

 Nova Scotia (10s, Si, I3g). 



