Lets say data1 is the column time data
diff_data=diff(data1);
idx_delete=find(diff_data~=3600)+1;
% +1 for compensate with next
% Do modify accordingly
Once get the rows numbers, which to be deleted
matrix(idx_delete,:)=[]
Or:
matrix(~mod(data1,3600)==0,:)=[]
It gives the all those numbers, which are non divisible by 3600
