A Christian dies intestate leaving lineal descendants, but all of them are not of same degree of relationship. What is the procedure for devolution of property?

To make the issue very clear we shall look into an example.  Mr. Stephen has two sons, Mr. Robert and Mr. Noble.

Mr. Robert dies before his father leaving behind two sons. Mr. Stephen dies leaving behind his one son Mr. Noble and two grand sons (children of Mr. Robert). Mr. Noble the only surviving son of Mr. Stephen will get 50% of the property and the remaining 50% will be shared equally between two grand sons.