How to Get last 50 river post

I want to get only last 50 river item and still have pagination, how to do that ?

for example

page 1 : 10 river item,

page 2 :10 river item

page 3 :10 river item

page 4 :10 river item

page 5 :10 river item

total : 50 river item, and only 50river item will appear,

i will use elgg_list_river($options)

if i use 'limit'=>50, all 50 river item will appear in one page and there is no pagination,

is there database query to do this ?