YORKSHIRE TYPE AMMONITES Oct. 



Measurement Table 

 (Appendix Table I) 



Measure the fossil with compasses. Find the horizontal line which 

 most nearly coincides with this measure, using the thick diagonal as the 

 right hand boundary. The figures on the left give the actual size of 

 the fossil in inches and tenths, or in miUimetres. 



Measure the picture of the fossil from the same points. Place the 

 measure on the same horizontal line. If it fall short of the diagonal, 

 the figures on the top give the amount of reduction. If it fall beyond 

 the diagonal the figures on the right give the amount of enlargement. 



When a specimen has been depicted enlarged or reduced, its actual 

 proportions can be ascertained by using for the right diagonal the number 

 which corresponds with the amount of difference stated. 



For ascertaining the proportion of height or thickness of whorl, 

 or size of umbilicus to the diameter, radius, or other base-line, measure 

 their amounts upon the horizontal line which coincides with length 

 of base-line. The diagonals will give the percentages. For large fossils 

 halve, quarter, or reduce the length of base-line until a workable limit 

 be reached ; then halve, quarter, or similarly reduce the other measures 

 or the results. 



