Hello Dhouha,

I believe you are preparing a range chart to show vertical/stratigraphic distribution of all the ostracod species. This range chart can be used to depict taxon range zones and assemblage zones. In addition, other biozones, viz. concurrent range zones, interval zones, phylozones, etc. can be also demonstrated using the same range chart.

Best wishes

Dear Sengupta, 

Yes i did the vertical distribution of the encountered ostracods but I have some confusing on how to determine the ostracod assemblege which characterize the biozone. 

Best regards,

Hello Dhouha,

You may go through the concept and procedures outlined in the following link, please.

http://stratigraphy.org/upload/bak/bio.htm

Hope, it helps.

Best wishes

Thank you very much.

Best regards,