There are no Croals listed on the Bouchenrouder maps. However, if we look at the records of Legacies of British Slavery, (http://www.ucl.ac.uk/lbs/
) you will find quite a few Croals receiving compensation. Similarly, there is a list of plantations for 1860 which shows quite a few Croals. Finally, John Croal was of course the first mayor of Georgetown (http://www.nationaltrust.gov.gy/new/index.php?option=com_con...
). So, in short, during the 19th century there may have been quite a few Croals in Guyana who could have been the ancestor to James August. You may have to work your way back from any information you may have on your grandfather, like his parents. Your problem is not to find Croals in Guyana's history, but the right one(s)!