Please could someone help me with some a Numbers function?

I'm counting sedimentary clasts tomorrow (don't ask...) and I need a spreadsheet to help me crunch the numbers.

I made little drop down menus yesterday so it's easy to input the clast type.



However, I need the total number of that type of clast in a different table (so I can ultimately make a pie chart of clast proportions).

Eg, if I see 25 Calcite clasts, I'll have selected "calcite" 25 times from the drop-down menus, and I need "25" to appear in the table in the screen shot below.

I think it's something to do with the SUMIF() function but I can't get it to work properly.



I hope explained myself properly! Thanks

PS: apologies for the mistake in the thread title!