AET. 4 CAMBRIAN CONCHOSTRACA — ULRICH AND BASSLER 117 



Plate 7 



Figures 1, 4, 5, 9, 10, 11, 20-27, 29-32, 35, are after Matthew and Figures 

 13-19, after Wiman. 



Page 

 J'lGTJRES 1-3. Beyrichona tinea planata Matthew (see also pi. 6, figs. 3,4) __ 45 



1. Matthew's figure of the type specimen, X 4, of 



Beyrichona planata. 



2. A drawing of Matthew's type D of Beyrichona 



planata X 4. 



3. Matthew's type B of Beyrichona planata X 4. 



Lower Cambrian (Hanfordian, C162): Hanford 

 Brook, New Brunswiclc. 

 4. Beyrichona tinea Matthew (see also plate 6, figs. 1, 2, 5-7) __ 43 

 The type specimen, a left valve, X 4. 



Lower Cambrian (Hanfordian, (C1&2) : Hanford 

 Brook, New Brunswick. 

 5-7. Beyrichona papilio Matthew (see also pi. 6, fig. 11) 43 



5. The type specimen, X 4, showing two valves in 



position. 



6. A sketch of Matthew's type B of Beyrichona tri- 



angula X 4. 



7. Outline drawing of Matthew's type C of Beyrichona 



triangula X 4. 



Lower Cambrian (Hanfordian C163) : Hanford 

 Brook, New Brunswick. 

 8,9. Beyrichona tinea triangula (Matthew) (see also pi. 6, figs. 



8-10) 44 



8. Sketch of Matthew's type A of Beyrichona triangula 



X 4. 



9. Matthew's figure of this species, X 4. 



Lower Cambrian (Hanfordian C163) : Hanford 

 Brook, New Brunswick. 



10. Beyrichona ovata Matthew 47 



The type specimen, X 4, showing extremely short 



hinge line. 

 Lower Cambrian (Hanfordian C162): Hanford Brook, 

 New Brunswick. 

 11, 12. Beyrichona rotundata Matthew (see also pi. 6, fig. 12) 46 



11. Matthew's view of the type specimen, X 4. 



12. Drawing of the same specimen after matrix had 



been removed. 

 Lower Cambrian (Hanfordian C163) : Hanford 

 Brook, New Brunswick. 



13. Beyrichona alta Wiman 48 



An imperfect right valve, X 8. 



Lower Cambrian, Olenellus sandstone: Limon near 

 Gefle, Sweden. 



