The most common and most likely answer to this crossword clue is the 7 letter word LAMINAR
I've seen this crossword clue in The Daily Telegraph
L
A
M
I
N
A
R
More clues leading to the result LAMINAR
- Halt, stopping short, with awful rain in sheets
- Dealing with plates smashed in alarm
- River creature from the south with thin bony scales
- Blow with awful rain as sheet upon sheet
- At the heart of Vellore, Mani constructed a road made of layers
- Like some rocks beast knocked over by river
- River creature upset concerning fluid flow
Buddy explains!

The straight part
We know that "Like some rocks" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case like some rocks = laminar.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does LAMINAR mean?
LAMINAR adjective- Of fluid motion, smooth and regular, flowing as though in different layers.
- In, or consisting of, thin plates or layers.