40 



FAUNA OF THE CORNBRASH. 



Of the 200 examples of Macroc&phalites examined, a selection of 37 lias been 

 taken, which are undoubtedly from the Cornbrash, and which afford fairly exact 

 measurements. 



Tablk I. — Comparative Measures of Cornbrash Macroeephalites . 



A. Diameter in millimetres. B. Percentage ratio of transverse diameters 



C. Pei'centage ratio of last whorl. D. Percentage ratio of thickness. 



E. Number of outer ribs in last half -whorl. F. Ratio of outer to inner ribs. 



C. Compressus. M. Macrocephalus. Hh. Hudlestoni. T. Typlcus. H. Herveyi. 



No. 



A. 



B. 



C. 



D. 



E. 



F. 



Locality. 



Species. ; 



1 



23 



81 



48 



44 



45 





Scarborough 



T 



2 



25 



83 



42 



73 



28 



2-8 



„ 



M 



3 



30 



85 



50 



52 



29 



2-25 



Ailsworth 



Hh 



4 



31 



81 



48 



45 



50 



— 



Bedford 



C 



5 



34 



85 



50 



43 



43 



3 



Appleby 



T 



6 



37 



81 



43 



71 



26 



2-5 



Peterborough 



M 



7 



39 



86 



43 



51 



28 



2-5 



Appleby 



Hh 



8 



43 



82 



48 



72 



28 



3? 



Kushden 



M 



9 



44 



86 



50 



70 



27 



2-8 



Scarborough 



M? 



10 



44 



86 



43 



64 



30 



2-5 



Bedford 



H 



11 



48 



85 



45 



56 



30 



2-75 



Rushden 



Hh 



12 



49 



82 



50 



45 



42 



3 



Scarborough 



T 



13 



52 



82 



46 



71 



30 



22 



,, 



M 



14 



53 



85 



51 



75 



31 



2-4 



,, 



M 



15 



53 



80 



51 



43 



39 



3 



Stilton ? 



T 



16 



57 



86 



45 



68 



27 



22 



" Herveyi," Tjpe I 



H 



17 



65 



83 



37 



48 



34 



3 



Scarborough 



T 



18 



66 



82 



51 



49 



41 



3-2 



,, 



T 



19 



73 



82 



52 



49 



33 



2-5 



t) 



Hh? 



20 



74 



84 



46 



70 



32 



2-6 



Lincolnshire 



H 



21 



78 



81 



51 



44 



49 



2-9 



Scarborough 



T 



22 



81 



80 



45 



58 



24 



2 2 





H? 



23 



83 



82 



49 



47 



44 



32 



Peterborough 



T 



24 



87 



85 



48 



72 



28 



21 



Castor 



M 



25 



91 



81 



52 



54 



40 



27 



Fairford 



T 



26 



92 



82 



52 



78 



30 



2-4 



Scarborough 



M 



27 



93 



84 



52 



48? 



47 



3 



Peterborough 



T 



28 



94 



87 



52 



65 



33 



275 



Scarborough 



H? 



29 



96 



85 



46 



73 



29 



2-8 



Bedford 



M 



30 



100 



80 



48 



42 



42 



26 



Scarborough 



T 



31 



105 



83 



50 



42 



48 



2-8 



Castor 



T 



32 



105 



80 



45 



60 



30 



2-6 



Peterborough 



H 



33 



109 



80 



48 



44 



32 



2 



Northants 



H 



34 



110 



82 



45 



50 



39 



3 



Thrapston 



Hh 



35 



113 



80 



51 



47 



44 



36 



Scarborough 



T 



36 



138 



82 



43 



64 



30 



2-2 



" Herveyi," Type II 



H 



37 



355 



82 



53 



42 



66? 



— 



Garsdon 



C 



In this list, arranged according to size, we see that little change takes place in 

 B, on which the curvature depends, and which varies only from "80 to *87, or 

 in 0, on which the overlapping depends, which varies only -42 to '53 ; for all the 

 examples are of the same genus, but the relative thickness ranges from *42 to "78, 



