"Pois Chiche Casse" which may be Bengali or Pakistani for chickpeas who knows! I only speak broken English
It's French, literally means broken chickpea ie split chickpeas .
Wiki says that Chana dal is produced by removing the outer layer of kala chana (black chickpeas) and then splitting the kernel.
Other places on the web say that Bengal gram is also the name of small brownish black chickpea and chana dal is made by removing the outside skin and splitting it.
If you read the Mendosa article, he found that there are 2 groups of chickpeas, one larger and fatter originally from Afganistan, the other smaller and dark skinned which seems to be associated with India. They are the same species so may be interbred. I think that probably means that there may be several varieties called chana dal. Even packets from the same producer could easily come from different growers/varieties . Unfortunately this might mean varied GIs (like varieties of rice or potatoes ).